An interim analysis of vaccine trial data submitted to the FDA11 showed a disproportionate, but not statistically significant, number of cases of grade 2 or 3 cervical intraepithelial neoplasia related to nonvaccine HPV types among vaccinated women.

In analyses by lesion type, the efficacy appears to be significant only for grade 2 cervical intraepithelial neoplasia; no efficacy was demonstrable for grade 3 cervical intraepithelial neoplasia or adenocarcinoma in situ.

Buried in the data of the report is the effectiveness of the vaccine in preventiong precancerous lesions called cervical intraepithelial neoplasia for any type of papilloma virus – only a 52% reduction overall.